Luffing mechanism for jib-cranes



J. N. GOUDIE. LUFFING. MEGHANISM FOR JIB CRNES.

APPLICATION FILED ocT. I. 1919.

1,338,726. y Patented May 4,1920.

am /Snani/ x Mofa.,

zzz/70a JOHN NICOLSON GOUDIE, OF HUNTERS QUAY, SCOTLAND.

LUFFING MECHANISM FOR JIB-CRANES.

Application filed October 1, 1919.

To all whom t may concern:

Be it known that I, JOHN NicoLsoN Gomma, a Subj ect of the King of the United Kingdom of Great Britain and Ireland, and residing at Hunters Quay, Firth of Clyde, Scotland, have invented a certain new and useful Improvement in Lu'fling Mechanism for Jib-Cranes, of which the following is a specification.

This invention relates to jib cranes which are designed to luif the load along a horizontal path and it consists in an improved luing mechanism comprising a rocking beam fulcrumed in the free end of the jib and equipped at opposed ends with pulleys wrapped bythe hoisting rope, and means for rocking the beam, the arrangement being such that the vertical component of the outward movement of the lower pulley is balanced by the oppositely directed vertical component of the inward movement of the upper pulley whereby the load is lufed in a substantially horizontal path.

The invention is illustrated in elevation in the ligure of the accompanying drawing.

As shown the improved luing mechanism comprises a rocking beam A fulcrumed at B on the free end of the jib C and equipped at its upper end with a pulley D and at its lower end with a pulley E, the requisite rocking movement being imparted to the beam by means of a suitable rod F connected to a bell-crank-lever G operable by a hand controlled screw and nut mechanism as at II under the control of the operator.

The hoisting rope I, which is coiled around a suitable hoisting drum K and passes over a guide pulley L, embraces'the pulleys D, E, and is preferably held against disengagement from the pulley E by a guard M.

When it is desired to luf the load, it is requisite merely to rock the beam A into a position such as is indicated by the dotted lines.

It will be readily seen that the vertical component of the outward movement of the lower pulley E is balanced by the oppositely directed vertical component vof the inward movement of the upper pulley D and that Specification of Letters Patent.

Patented May 4, 1920.

Serial No. 327,641.

the load will be constrained to follow a substantially horizontal path. The base of the jib is preferably mounted in a ball bearing N provided with feet O permitting insertion under the base of a suitable jacl-up truck. The base 'may be secured to a floor by suitable ties P.

I claim 1. The combination with a jib of a rocking beam fulcrumed in the free end of said jib, two pulleys one disposed at the upper end of said beam and one disposed at the lower end of said beam, a hoisting rope wrapping said pulleys and means for rocking said beam, the disposition of the fulcrum of the beam in relation to the pulleys being such that the vertical component of the outward movement of the lower pulley is balanced by the oppositely directed vertical component of the inward movement of the upper pulley whereby the load is luffed in a substantially horizontal path, substantially as described.

2. rIhe combination with a jib of a rocking beam fulcrumed in the free end of said jib, two pulleys one disposed at the upper end of said beam and one disposed at the lower end of said beam, a hoisting rope wrapping said pulleys and a bell-crank lever on said jib, a rod operatively connecting said beam with said bell-crank lever and manually operable screw and nut mechanism for operating said bell-crank lever for rocking said beam, the disposition of the fulcrum of the beam in relation to the pulleys being such that the vertical component of the outward movement of the lower pulley is balancedk by the oppositely directed vertical component of the inward movement of the upper pulley whereby the load is lufl'ed in a substantially horizontal path, substantiallyl as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

JOHN NICOLSON GOUDIE.

Witnesses KATE FOTHERINGHAM, ISABEL ROLLO. 

